Institute of Anatomy and Cell Biology, University of Heidelberg, INF 307, 69120 Heidelberg, Germany; WIN Olfactory Dynamics Group, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
Neuron. 2010 Feb 11;65(3):399-411. doi: 10.1016/j.neuron.2010.01.009.
Local inhibitory circuits are thought to shape neuronal information processing in the central nervous system, but it remains unclear how specific properties of inhibitory neuronal interactions translate into behavioral performance. In the olfactory bulb, inhibition of mitral/tufted cells via granule cells may contribute to odor discrimination behavior by refining neuronal representations of odors. Here we show that selective deletion of the AMPA receptor subunit GluA2 in granule cells boosted synaptic Ca(2+) influx, increasing inhibition of mitral cells. On a behavioral level, discrimination of similar odor mixtures was accelerated while leaving learning and memory unaffected. In contrast, selective removal of NMDA receptors in granule cells slowed discrimination of similar odors. Our results demonstrate that inhibition of mitral cells controlled by granule cell glutamate receptors results in fast and accurate discrimination of similar odors. Thus, spatiotemporally defined molecular perturbations of olfactory bulb granule cells directly link stimulus similarity, neuronal processing time, and discrimination behavior to synaptic inhibition.
局部抑制回路被认为可以塑造中枢神经系统中的神经元信息处理，但目前尚不清楚抑制性神经元相互作用的特定特性如何转化为行为表现。在嗅球中，通过颗粒细胞抑制僧帽细胞/丛细胞可能通过细化气味的神经元表示来促进气味辨别行为。在这里，我们表明，选择性删除颗粒细胞中的 AMPA 受体亚基 GluA2 会增强突触 Ca(2+)内流，从而增强对僧帽细胞的抑制。在行为层面上，相似气味混合物的辨别速度加快，而学习和记忆不受影响。相比之下，选择性去除颗粒细胞中的 NMDA 受体则会减缓对相似气味的辨别。我们的结果表明，由颗粒细胞谷氨酸受体控制的对僧帽细胞的抑制导致对相似气味的快速准确辨别。因此，嗅球颗粒细胞的时空限定分子扰动将刺激相似性、神经元处理时间和辨别行为直接与突触抑制联系起来。
